FR2611234A1 - ELECTRONIC DISTRIBUTION TYPE IGNITION DEVICE FOR MULTI-CYLINDER INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

THE INVENTION CONCERNS AN IGNITION DEVICE OF THE ELECTRONIC DISTRIBUTION TYPE FOR AN INTERNAL COMBUSTION ENGINE WITH SEVERAL CYLINDERS. THIS DEVICE INCLUDES A PLURALITY OF IGNITION CIRCUITS EACH PROVIDED FOR ONE OR TWO OF THE ENGINE CYLINDERS AND CONTAINING A 4 TO 9 IGNITION COIL AND A 20 TO 25 POWER SWITCHING ELEMENT, AND A PLURALITY OF PROVIDED IGNITION SYSTEMS EACH FOR MORE THAN ONE OF THE SAID IGNITION CIRCUITS AND CONTAINING A SINGLE CURRENT LIMITATION CIRCUIT 17, 18, 19 SERVING CURRENTS THROUGH THE POWER SWITCHING ELEMENTS OF THE ASSOCIATED IGNITION CIRCUITS. APPLICATION IN PARTICULAR TO INTERNAL COMBUSTION ENGINES FOR MOTOR VEHICLES.

Description

The present invention relates to a device for

  ignition for an internal combustion engine.and more particularly

  an ignition device of the type with electronic distribution

  for a multi-cycle internal combustion engine

  lindres. A conventional ignition device is known

  for an internal combustion engine, which is described in JP-

  A-60-209667 and wherein a feedback circuit of

  taking current sensing means is used to control the current in a switching device to control the interruption of the primary current of a coil

  ignition. In the application of this type of device

  to a multi-cylinder internal combustion engine, it is recommended that part of this device be used

  in common in order to avoid a multiplication of

  and therefore an increased cost. Specifically,

  a conventional ignition device for a combustion engine

  internal two-cylinder bursion utilizes a current sensing resistor and a feedback circuit, or the like,

  for controlling the current of a pair of communication transistors

  mutation. In addition, JP-A-60-209668 discloses a device

  of ignition for an internal combustion engine having four

  eight or eight cylinders, and four power transistors

  to control the primary current of the ignition coil,

  these four power transistors comprising a common circuit

  with current detection and a common feedback circuit.

  But in the device of the prior art men-

  mentioned above, the fact that only one

  current and a single feedback circuit are used.

  in common by all switching devices makes it impossible to control all switching devices

  in the case where a given switching device is damaged

  caused by a short-circuit or the like, which

  breaks the ignition of all the cylinders, thereby stopping

engine.

  This is why the purpose of the present invention

  is to provide a distributor-type ignition device

  electronic system for an internal combustion engine with several

  cylinders with built-in safety operation, such as damage due to short-circuiting of a switch, do not cause interruption of operation

  all other switching devices.

  According to the present invention it is

  having regard to an ignition device of the electronically

  for a multi-cylinder internal combustion engine,

  which has an ignition circuit having an aluminum coil

  lumage and a power transistor for each cylinder or each pair of cylinders of the engine and wherein the circuit

  ignition is integrated in a plurality of ignition systems

  mage each having at least two circuit units

  each ignition system incorporating a cir-

  baked and common control of current for control

  of current flowing through the switching device of

  of the particular ignition system.

  According to another aspect of the present invention, there is provided an electronic distribution type ignition device for a multi-internal combustion engine.

  cylinders, arranged as described above and pre-

  sensing a high degree of safety and in which

  if one of the power switching devices is

  damaged by a short circuit, only the ignition system

  associated with the damaged power switching device has not

  its function, while the other systems of

  continue to operate, which has the effect that

  ignition of all the cylinders of the internal combustion engine

  is not stopped, which prevents the engine from stopping.

  Other features and advantages of the pre-

  invention will be apparent from the description given hereinafter

  reference is made to the accompanying drawings, in which: FIG. 1 represents the diagram of a circuit

  showing an ignition device in accordance with this

  vention; FIG. 2 is a diagram showing waveforms for explaining the operation of the ignition device shown in FIG. 1; - Figure 3 shows the diagram of a circuit

  showing an embodiment of the lighting device

  mage according to the present invention; FIG. 4 is a partially cut-away sectional view showing the arrangement of a power module of the ignition device shown in FIG. 3; and - Figure 5 shows the diagram of a circuit

  showing another embodiment of the present invention

tion.

  An embodiment will be described below

  of the present invention with reference to the accompanying drawings.

  FIG. 1 represents a circuit of a device

  ignition circuit of the electronic distribution type for an internal 6-cylinder internal combustion engine, to which

  the present invention is applicable. The cylinders of this model

  6-cylinder engine have spark plugs 10 to 15,

  one for each cylinder, such as for example a candle

  mage 10 for the first cylinder, a spark plug 11 for the sixth cylinder, a spark plug 12 for the

  fifth cylinder, and a spark plug 13 for the

  fourth cylinder, a spark plug 14 for the third

  cylinder and a spark plug 15 for the fourth cylinder

  dre, to achieve ignition in each cylinder. These cycles

  linders are arranged for example in the order of

  first, fifth, third, sixth, second

and fourth cylinder.

  The six spark plugs 10 to 15 are connected

  corresponding respective ignition coils 4 to 9, the primary coils of which are connected in series to

  transistors of power 20 to 25. The transistors of

  20 to 25 interrupt the primary current of the ignition coils 4 to 9 so as to produce a high voltage in

  the secondary coils of these ignition coils, for the

  lighting the spark plug. An ignition circuit is thus obtained constituted by the ignition coils 4 to 9 and the

power transistors 20 to 25.

  As can be seen in the drawings, the circuit of

  The lighting system is subdivided into three ignition systems each comprising two ignition circuit units. In the form

  embodiment shown, a unit forming an ignition circuit

  mage including the ignition coil 4 and the power transistor

  20, and an ignition circuit unit including the ignition coil 5 and the power transistor

  a first ignition unit; a circuit unit of

  lighting and including the ignition coil 6 and the transistor

  22 and an ignition circuit unit

  the ignition coil 7 and the power transistor 23 constitute a second ignition unit; and an ignition circuit unit and including the ignition coil

  8 and the power transistor 24 and a circuit unit

  ignition cooker including the ignition coil 9 and the transistors

  tor of power 25 constitute a third unit of

  ge. The first, second and third ignition units are connected via respective fuses 100, 101 and 102 and via a key switch 2 to a

  battery 1 of a vehicle, which delivers power to the vehicle

  ogy. On the other hand, the battery 1 is connected to the

  power supply terminal of a microcomputer (some

  hereinafter referred to as "the computer") 3

  through the key switch 2. This computer

  3 is powered by output signals delivered by

  different sensors detecting the operating conditions

  motor speed, including the engine speed (rpm), the cooling water temperature (TW), the battery voltage (VB) and the throttle opening degree (OT). gas, and control, according to these output signals, the duration of supply of the ignition circuit so as to adjust the ignition sequence to an optimum level depending on the operating conditions of the engine. The output signal of the computer 3 is sent to a power switching module 7 containing the six power transistors 20 to 25. Specifically, the computer 3 sends a control signal to the base terminal of each six

  transistors of power 20 to 25 and, in this way,

  conductive-secure operation of these tran-

power sistors.

  The power switching module 16 is also

  subdivided by the ignition systems in such a way

  that the pairs 20, 21, 22, 23 and 24, 25 of the power transistors

  respectively constitute these ignition systems. Cha-

  one of these ignition units has a common current limiting circuit. The two power transistors 20, 21 of the first ignition system, for example, share

  the use of a common circuit 17 for limiting the

  rant. This current limiting circuit 17 comprises only one

  the current detection resistor 17a, connected between the emitters of the power transistors 20, 21 and the earth, by dividing the resistors 17b, 17c connected in parallel with the current detection resistor 17a, a current control transistor 17d, whose base is connected to a neutral point of the drive resistors and whose base is connected to ground, and diodes 17e, 17f connected in

  the direct direction between the collector of the transistor 17d com

  the current and the bases of the two power transistors

  this 20,21. The two power transistors 22, 23 constituting the second ignition system also comprise a circuit

  current limitation of the current, and the other two

  24,25 power sistors constituting the third ignition system are provided with a common limiting circuit 19

  of the current. These current limiting circuits are also

  incorporated in the power switching module 16. Hereinafter the operation of the ignition device described above will be explained. Waveforms

  (a) to (f) shown in FIG.

  applied to the bases of the power transistors 20 to from the computer 3. More specifically, the

  Figure 2 (a) represents the signal applied at the base of the

  power sistor 20 for controlling the ignition of the first cylinder, FIG. 2 (b) shows the signal applied to the base of the power transistor 22 for the fifth cylinder,

  Figure 2 (c) represents the signal applied to the base of the

  power sistor 24 for the third cylinder, Fig. 2 (d) shows the signal applied to the base of the power transistor 21 for the third cylinder, Fig. 2 (e)

  represents the signal applied to the base of the transistor of

  23 for the second cylinder, and Figure 2 (f) represents

  the signal applied to the base of the power transistor for the fourth cylinder. In this way, the computer 3 produces an ignition control signal (basic signal)

  for each cylinder, without overlapping the signals

ignition control.

  The circuits 17, 18 and 19 for limiting the

  have the same configuration and assume the same

  functions and that is why the following is

  cation for the current limiting circuit 17, to be

  be an example. The current detection resistor 17a of the

  current limiting circuit 17 is connected to the transmitters

  of the power transistors 20 and 21 so as to de-

  detect the current entering it. Specifically, this cou-

  rant begins to flow in the detection resistor 17a

  current, a voltage proportional to this current

  to the limits of this resistance. This voltage signal is

  divided by the division resistors 17b, 17c and is

  at the base of current limiting transistor 17d. Lors-

  that the current flowing through the power transistor 20 or 21, i.e. the primary current of the ignition coil 4 or 5, reaches a predetermined value, the current limiting transistor 17d starts to conduct. As a result, the ignition control signal applied to the power transistor 20 or 21 is transmitted to ground via the 17e or 17f diode connected to the

  the forward direction and also to the control transistor 17d

  in the conductive state, as indicated above. The ignition control signal sent to the power transistor 20 or 21 is controlled in this manner, thereby

  the maximum value of the primary current of the ignition coil

  at a predetermined level. The shape of the primary current of the ignition coil 4 thus controlled is shown in FIG. 2 (g). In addition Figure 2 (h) represents the way

  high voltage is produced for the ignition of the

  ignition source 10 located in the first cylinder, that is,

  the secondary voltage of the ignition coil 4.

  specific period when the primary coil current

  4 shown in FIG. 4 (g) is cut off, a

  high-voltage ignition signal is produced by the sta-

  until now in the primary coil.

  As is apparent from the embodiment described above, an ignition device according to the

  present invention comprises a plurality of circuits for

  mage each containing an ignition coil and a power transistor and grouped into a plurality of systems, or, more specifically, six ignition circuits are grouped into three systems and are integrated. As a result, even in the case where one of the power transistors is damaged by a short circuit for any reason, only the system associated with that particular transistor becomes inactive, while the other systems can operate.

  normally, which improves the intrinsic safety of the

  positive ignition as a whole.

  In Figure 1 for example, it is assumed that the power transistor 20 is damaged by a short circuit, for any reason. (In general the damage of a transistor, if it occurs, appears in its junction, which bypasses the latter). A current flows continuously through the current detection resistor 17a, and the current limiting transistor 17d is maintained in the state

  excited. The basic signal applied at the base of the other

  power sistor 21 located in the same system, that is.

  say an ignition control signal is unwantedly transferred to ground via the control transistor 17d which is thus kept in the excited state, so

  that the power transistor 21 is kept in the closed state

  than. The primary current does not enter the coil of

  lighting 5, which prevents ignition of the ignition coil

(of the sixth cylinder).

  If current limiting current is described

  above was used by all the cylinders (six

  lindres for example) as in the prior art, the damage

  caused by the short circuit of a power transistor de-

  written above would stop ignition in all cylinders, which would stop engine operation. In others

  terms, if short-circuit damage such as

  born above occurs while the car is traveling, this last

She stops rolling and stalls.

  On the contrary, in accordance with the

  according to the present invention, including a circuit for

  mage having ignition coils and power transistors distributed and integrated in a plurality of systems

  each having a current limiting circuit, an

  possible damage of the power transistor 20 by short

  circuit makes inactive the ignition coils 4,5 which put under tension the spark plugs 10,11 located in the

  first and sixth cylinders, while maintaining the function

  normally the ignition coils 6,7 triggering the ignition

  mage in the fifth and second cylinders, the coils of

  lighting 8.9, which triggers ignition in the third and fourth

  third cylinders, and the power transistors 22 and 25

  used to control the primary current of the ignition coils.

  As a result ignition is effected in four of the six cycles.

  linders, which prevents the engine from stopping, allowing

  to drive to a dealer or the like for repair

appropriate

  In accordance with the embodiment

  previously, in which the first, fifth, third

  s, sixth, second and fourth cylinders in the firing order are divided into three two-cylinder systems containing pairs of cylinders respectively formed by

  the first and sixth cylinders, the fifth and second

  lindres and the third and fourth cylinders so as to maintain the operation of the engine in a uniform state,

  well-balanced, in the case of damage due to short-

  circuit and the inactive state of the transistor of

  one of the systems. In Figure 1, the systems of

  lumage have respective fuses 100 to 102, which are

  adapted to melt if a power transistor is damaged

  misled by a short circuit. As a result, the system of

  The lumen containing the power transistor damaged by the short circuit is disconnected from the power supply, which reduces the power loss, i.e. the energy loss.

drums.

  Figure 3 shows another form of

  of the present invention. As is evident from the drawing, an ignition circuit for a six-cylinder engine is subdivided into two systems using MOS transistors

  FET 20 'to 25' as power switching devices

  ciency. Specifically, a first ignition system com-

  carries ignition coils 4.8 and 7 to power the

  spark plug 10 for the first cylinder, the candle of

  lumage 14 for the third cylinder and the spark plug 13 for the second cylinder, the last MOS FET transistors of power 20 ', 24' and 23 '. The other system consists of ignition coils 5, 6 and 9 for supplying the ignition coil 12 for the fifth cylinder, the coil

  11 for the sixth cylinder and the ignition coil

  ge 15 for the fourth cylinder, and FET MOS transistors

  22 ', 21', 25 ', connected in series with these candles.

  As part of this arrangement, ignition is effected in

  first, fifth, third, sixth, second and fourth

  cylinders in this order, as in the first embodiment shown in FIG.

  obviously of this configuration, in accordance with this

  realization, the ignition circuits of the first and second

  cond systems are distributed sequentially according to the ignition order so that even if one of the systems

  becomes defective as a result of the damage to the

  Tor MOS FET power by a short circuit, the other systems

  three cylinders continue to operate normally, allowing the motor to be driven in a uniform manner,

in a balanced state.

  Current limiting circuits 170 and 180,

  which are contained in the ignition systems, possess

  sibly the same function as those shown in the figure

  1. The current limiting circuit 170, for example,

  carries a current detection resistor 170a, resists

  170b, 170c, a voltage control transistor 170d, and three 170e, 170f, and 170g diodes connected

  in the direct direction and connected to the sources of three

  MOS FET power sistors 20 ', 24', 23 '.

  A power MOS FET transistor is itself a voltage control device, whose drain current (source) can be controlled by means of the application of a

  constant voltage at the gate of the transistor. But in the gam-

  4 to 6A currents used for an ignition system, on the one hand it is difficult to control the gate voltage, and on the other hand an unstable maximum value of the drain current (source) is produced under the effect of variations in the power MOS FET transistor. Specifically the

  control of the maximum value of the drain (source) by the com-

  the gate voltage is subject to a certain amount of

  mitation. It is for this reason that in the form of reali-

  In FIG. 3, a transistor 170d or 180d is used and the gate voltage is controlled by the use of the voltage VCE (sat) of the transistor 170d. When the source current of a MOS FET power transistor (such as 20 ')

* reaches a predetermined value, the transistor 170d is

  driver and controls the gate voltage so that

  constant nir the source current. It follows that the pre-

  control of the current limit value is strong-

  improved compared to the conventional control process.

  constant of the gate voltage. The other parts of the circuit shown in FIG. 3 are identical to those

shown in Figure 1.

  In the embodiment of Figure 3,

  if one of the power switching devices is short-circuited and damaged, the other ignition systems

  continue to run the engine. However, contrary

  1, in which the output power of the motor is reduced to two thirds of its value, the output power of the motor becomes equal to the embodiment of FIG.

  to half that obtained in the embodiment

  flabbergasted. This is because ignition is subdivided into

  two systems and not three systems. Despite this

  Convenient, the embodiment shown in FIG.

  3 has the advantage of significant savings and

  because there are only two cir-

  baked current limiting and two fuses.

  Figure 4 shows an arrangement of the transistor

  MOS FET and the power switching device, installs

  on a single silicon chip. In the view in

  section of Figure 4, the devices are formed on a subset

  The reference 200 denotes a metallic layer

  able to be fixed by welding to a non-heat sink

  represent. Reference 201 designates a P-type layer

  strung to the most negative potential (mass). The reference 202

  denotes an insulating layer formed by a silicon oxide.

  The hatched part marked by the reference 203 is an elec-

  aluminum trode which is formed by evaporation deposition.

  The elements designated by references 2, and 3 are

  MOS FET transistors of power, the desired reference

  a drain, the reference 2 a grid and the reference (a source, the elements and e are also

  MOS FET transistors of power, the reference

  a source, the reference Q a grid and the reference

  this a drain. The electrodes @, G and Q form a resistor. A diffusion-formed resistor is formed in the P-type layer between the electrodes and (6) by connecting the electrode 4 to the most positive potential (positive battery voltage). On the other hand

  elements designated Q and Q denote a diode

  a PN junction, and the references 0, 'and (de-

  sign the current limiting transistors. Reference

  this (designates a base, the reference Q an issuer and the

reference O a collector.

  A plurality of MOS FET transistors for power

  they are formed in this way on a single silicon chip and further, thanks to the use of the layers

  type N and P-type silicon.

  flow can be formed on a single micropla -

  quette. As a result, the devices can be connected

  collectively by means of a vapor deposition of aluminum

  between contacts, which greatly improves the reliability

  the connector compared to the conventional process

  welding and wiring. Similarly, it is pos-

  to reduce the number of elements so as to reduce the dimensions of the power switch, which provides

  a cheap ignition system with a high degree of

  mounting and requiring shorter processing.

  The power switching devices can

  may be constituted by power transistors instead of power MOS FET transistors. A power switch arranged in the manner shown in FIG. 4 can be used not only for the circuit of FIG.

  1, but also for a distribution and lighting system

  electronic type of simultaneous ignition type, shown

  Figure 3. The reliability of the connectors is therefore

  improved with a simultaneous reduction of the dimensions

  the power switching device.

  In the embodiments mentioned above,

  previously, each ignition system having a plurality of power switches and a current limiting circuit is formed on a single semiconductor substrate. In

  the embodiment shown in FIG. 1, for example

  pl, the power transistors 20,21 and the current limiting circuit 17 are made in the form of a single

  system on a single semiconductor substrate, the transistors

  power of 22,23 and circuit 18 of

  are formed, so as to form another system, on another semiconductor substrate, and the power transistors 24, 25 and the current limiting circuit 19, constituting another system, are fixed on another semiconductor substrate, which constitutes a switching module of

  16. Specifically, two communication devices

  power circuit and a current limiting circuit are formed on each of the three semiconductor substrates,

  and three sets of this kind are used to control

  der the ignition of a six-cylinder engine.

  On the other hand, in the embodiment of

  3, three power MOS transistors FET and a circuit

  current limiting circuit, each constituting an ignition system, and two semiconductor substrates are used

  to form a power switching module.

  As explained above, we are

  different ignition systems on different semi- substrates

  drivers so as to be sure that even when the

  switching device of an ignition system

  given ge is damaged by a short circuit, the other sys-

  are kept intact, which ensures safety and security.

  precise ignition operation of the other systems of

  Lumage. In the case where an ignition system is constituted

  two power transistors and one limiting circuit

  flow, as in the embodiment of the

  1, two sets of this output can easily be used.

  in a four-cylinder engine, and use four

  like this in an eight-cylinder engine. The

  ignition circuit according to the embodiment

  shown in Figure 3 may comprise a single circuit of

  the expected current for each set of three

  positive power switching, which provides the advantage

  a layout at a reduced cost. If we use

  MOS FET sistors to constitute the power transistors

  arranged on the semiconductor substrates, in particular, one obtains

  maintains relatively low power consumption, with increased integrity, making the circuit suitable for

a compact ignition system.

  FIG. 5 shows another form

  embodiment of the invention, applied to a lighting system

  Simultaneous ignition type mage for an eight-cylinder

  lindres. In FIG. 5, the elements or components designated by the same reference numerals as those of FIG.

  designate the same elements or components as on this

  In this embodiment, the secondary coils

  ignition coils 401, 402, 403 and 404 are connected to

  411,412,413,414,415,416,417, 418, and the secondary coil 404 of an eight-cylinder engine has spark plugs 411, 412, 413,414,415,416,

  417,418 connected to its terminals and distributed between the cylinders

  eight-cylinder engine. Similarly, high voltage diodes 421, 422, 423, 424 are inserted between one of the terminals

  of the secondary coil and the spark plugs

  ge $ 412,414,416.41. L3s primary chins of alluminium coils

  401,402,403,404 are connected in series with

  MOS power FET sistors respectively 431,432,433,434, whose grids are fed by a control signal delivered by a microcomputer 3. By placing in the conducting state and

  in the off state the power MOS FET transistors, it

  a high voltage appears at the terminals of the secondary coil of the ignition coils 401, 402, 403, 404 for triggering a spark in the ignition coils. In this embodiment, two spark plugs connected to the same ignition coil such as the ignition coils 411,412,

  connected to the secondary of the ignition coil 401, triggering

  a spark simultaneously. Similarly, we obtain the de-

  charge of a spark during the explosion stroke and

  the engine's relaxation stroke.

  The MOS FET transistors of power 431 and 432 previously mentioned constitute an ignition system and

  use in common a current limiting circuit 441.

  Similarly, the MOS FET transistors of power 433.434 form

  another system containing a similar circuit 442 of

  tation of the current. These circuits 441, 422 for limiting the

  are similar to those shown in Figure 3. Similarly, in this ignition system, even if one of the power MOS FET transistors of the two systems is damaged by a short circuit, the other elements of the system continue to to operate, which has the effect that the engine continues to be driven positively even when the power output is

reduced by half.

  Upon reading the above description,

  understand that, in accordance with the present invention, a

  failure due to damage to a given device

  shifting of power by a short circuit does not make the dis-

  positive inoperative ignition as a whole, which allows

  to obtain an ignition device of the type with electronic distribution

  for a multi-cycle internal combustion engine

  lindre, having an intrinsically higher operating safety.

Claims (5)

  1. Distribution type ignition device   electronic system, intended for use in a motor with   cylinders, characterized in that it comprises: a plurality of ignition circuits each provided for one or two of the engine cylinders and comprising   an ignition coil (4 to 9; 401 to 404) and a compression element   power transfer (20 to 25; 20 'to 25'; 431 to 434); and - a plurality of intended ignition systems   each for more than one of said ignition circuits and   as a single circuit (17,18,19; 170,180; 441,442) of limited   the current, for controlling currents flowing in the circuit power switching elements associated ignition.   2. Ignition device according to the claim   1, characterized in that the switching elements of   and the elements of the associated circuit for limiting   are formed on a common semiconductor substrate (201).   3. Ignition device according to claim 2, characterized in that said switching elements of   power are FET MOS transistors.   Ignition device according to claim 1, characterized in that each of said ignition systems comprises two of the power switching elements (20, 21; 22,23).   5. Ignition device according to the claim   1, characterized in that each of said lighting systems   mage has three power switching elements (20 ', 24', 23 '; 22', 21 ', 25').